The present invention relates to an internal structure of a primary exhaust duct of a turbomachine, to a turbomachine comprising such an internal structure, and to an aircraft comprising at least one such turbomachine.
A turbomachine conventionally comprises, from upstream to downstream, an air inlet via which the air enters the turbomachine, a motor which burns the air with fuel, and an exhaust duct via which the burnt gases are discharged.
Such a turbomachine generates noise when it is in operation.
In order to attenuate some of the noise, the turbomachine is surrounded by a nacelle comprising noise attenuating means such as, for example, honeycomb structures.
The low-frequency (between 300 Hz and 1000 Hz) sounds, particularly those associated with combustion, emitted by the turbomachine during take-off or landing form a significant source of noise in the environment and, in order to attenuate this noise, it is known practice to fit low-frequency sound attenuating devices in the structure of the primary exhaust duct (the English term “plug” is used for this).
The primary exhaust duct is situated in the continuation of the engine and in front of the jet pipe cone and its exterior primary wall is in contact with the stream of burnt gas coming from the engine.
Document U.S. Pat. No. 7,784,283 discloses the production of compartments separated by dividing partitions under the perforated primary wall of the primary exhaust duct in order to form Helmholtz resonators.
Such a device is effective although it is necessary to find new modes of embodiment.